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CVE-2026-43101
ipv6: ioam: fix potential NULL dereferences in __ioam6_fill_trace_data()
Published 2026-05-06 (5 months ago) by the Linux kernel CNA. Subsystem net/ipv6. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-43101 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | vulnerable | 6.1.190-1 | No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication. |
| Debian 13trixie | vulnerable | 6.12.113-1 | No fix published anywhere yet, neither in Debian nor upstream for the series trixie tracks. Watch the Debian tracker page for this CVE. Advisories for trixie have historically landed a median of 11 days after publication. |
| Debian 14forky | fixed | 6.19.14-1 | Update the kernel and reboot. Fixed in 6.19.14-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 6.19.14-1 | Update the kernel and reboot. Fixed in 6.19.14-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
We need to check __in6_dev_get() for possible NULL value, as suggested by Yiming Qian. Also add skb_dst_dev_rcu() instead of skb_dst_dev(), and two missing READ_ONCE(). Note that @dev can't be NULL.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
net/ipv6/ioam6.c
- What this is
- NETWORKING [IOAM]MAINTAINERS section matched on net/ipv6/ioam6* · Maintained
Check it on the machine
grep -w CONFIG_IPV6 /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
Show whether Debian builds this, per release
Debian builds this code. Every release below compiles the affected file into the kernels it ships.
- bookworm, trixie, forky, sidy
- y
- built into the kernel image on every flavour - only a patch removes it
- Build switch
- CONFIG_IPV6
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-05-06 (5 months ago)source
- CVSS
- 7.5 high
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsource recompute it - Attack vector
- network (AV:N)source
- EPSS
- 0.61%, higher than 48.1% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- net/ipv6
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.15 | 6.18.24 | 4198aab6f000 |
| 5.15 | 6.19.14 | 3719c234fa94 |
| 5.15 | 7.0 | 4e65a8b8daa1 |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:NAttack vector, network
- The vulnerable helper is reachable while processing IPv6 IOAM Hop-by-Hop options and IOAM LWT output for packets crossing an IOAM-enabled IPv6 node, so an attacker can trigger it with network traffic in a configured IOAM deployment.
- AC:LAttack complexity, low
- Once IOAM is enabled/configured on the target path, triggering only requires a valid pre-allocated trace with ingress/egress interface ID fields and a route/device state where `__in6_dev_get()` returns NULL; there is no race or difficult timing requirement.
- PR:NPrivileges required, none
- The attacker does not need credentials on the target to send the triggering IPv6 traffic; the administrative IOAM setup is a target deployment condition rather than an attacker privilege.
- UI:NUser interaction, none
- No victim user action is required after the vulnerable node is configured; packet processing alone reaches the dereference.
- S:UScope, unchanged
- The impact is within the same kernel/networking security authority and does not cross a VM, IOMMU, or similar boundary.
- C:NConfidentiality impact, none
- The bug is a NULL pointer dereference of missing IPv6 device state, not an out-of-bounds read or information disclosure primitive.
- I:NIntegrity impact, none
- The fixed issue does not provide attacker-controlled writes or data modification; it only prevents dereferencing NULL `inet6_dev` pointers.
- A:HAvailability impact, high
- A NULL pointer dereference in kernel packet processing can oops or panic the system, causing high availability impact.